Method for modifying graft polyolefins, compositions and articles comprising polyolefins modified thus

Abstract

Process for modifying a polyolefin grafted with acid or anhydride groups, by at least partial neutralization of these groups with at least one neutralizing agent comprising an organic salt (1) that releases an organic acid (I) during the neutralization, according to which the organic acid (I) derived from the neutralization of the grafted polyolefin is reacted with at least one inorganic salt (2). Modified polyolefin (that can be) obtained by the process described above. Polymeric composition containing (A) at least one polymer, and (B) at least one modified polyolefin (that can be) obtained by the process above. Article comprising the modified polyolefin or the composition described above.

1. A process for modifying a polyolefin grafted with acid or anhydride groups, by at least partial neutralization of these groups with at least one neutralizing agent comprising an organic salt (1) that releases an organic acid (I) during the neutralization, wherein the organic acid (I) derived from the neutralization of the grafted polyolefin is reacted with at least one inorganic salt (2) to form an inorganic acid (II) and an organic salt (3), and eliminating the inorganic acid by decomposition to form a gas. 
     
     
       2. The process according to  claim 1 , wherein the grafted polyolefin is selected from the group consisting of polymers of ethylene and of propylene, grafted with maleic anhydride. 
     
     
       3. The process according to  claim 1 , wherein the grafted polyolefin is a grafted block copolymer. 
     
     
       4. The process according to  claim 1 , wherein the organic salt (1) is liquid at the processing temperature. 
     
     
       5. The process according to  claim 4 , wherein the organic salt (1) is selected from the group consisting of Zn acetate and Na lactate. 
     
     
       6. The process according to  claim 5 , wherein the organic salt (1) and the inorganic salt (2) are introduced into the grafted polyolefin:
 simultaneously when the organic salt (1) is Na lactate; 
 in a deferred way when the organic salt (1) is Zn acetate. 
 
     
     
       7. The process according to  claim 1 , wherein the organic salt (1) is introduced into the grafted polyolefin in the form of an aqueous solution. 
     
     
       8. The process according to  claim 1 , wherein the inorganic salt (2) is selected from the group consisting of alkali metal carbonates, alkaline earth metal carbonates and rare earth metal carbonates. 
     
     
       9. The process according to  claim 1 , wherein the inorganic salt (2) is introduced into the grafted polyolefin in the form of an aqueous solution. 
     
     
       10. A process for modifying a polyolefin grafted with one or more of an acid and an anhydride group, comprising:
 at least partially neutralizing the acid and anhydride groups with at least one neutralizing agent comprising a first organic salt to form an at least partially neutralized polyolefin composition, wherein during the neutralizing the organic salt forms an organic acid; and 
 reacting the organic acid formed during the neutralizing with at least one inorganic salt to form an inorganic acid and a second organic salt; 
 decomposing the inorganic acid to form a gas; and 
 releasing the gas from the neutralized polyolefin composition. 
 
     
     
       11. The process of  claim 1 , wherein the partial neutralization is carried out in an extruder in which the polyolefin is present in the liquid form. 
     
     
       12. The process of  claim 1 , wherein eliminating the inorganic acid by decomposition shifts the neutralization reaction towards full neutralization of the polyolefin. 
     
     
       13. The process of  claim 10 , wherein the releasing shifts the neutralization equilibrium towards full neutralization of the polyolefin. 
     
     
       14. The process of  claim 10 , wherein the releasing forms an at least partially neutralized polymer composition that is free of inorganic acid. 
     
     
       15. The process according to  claim 1 , wherein the polyolefin is fully neutralized with the neutralizing agent and the organic acid (I) formed during the neutralizing of the polyolefin is fully reacted with the inorganic salt (2). 
     
     
       16. The process of  claim 10 , wherein the neutralizing is carried out with an amount of the first organic salt to completely neutralize the acid and anhydride groups of the polyolefin composition, and the organic acid is reacted with an amount of the inorganic salt to completely convert the organic acid to the inorganic acid and the second organic salt. 
     
     
       17. The process of  claim 10 , wherein the neutralizing is carried out with the first organic salt in an amount that is at least equimolar with the acid and anhydride groups of the polyolefin, and the organic acid is reacted with an amount of the inorganic salt that is at least equimolar with the amount of the organic acid.